EMI radiation from electronics mounted within a package or enclosure must be minimized in order to reduce or eliminate its potentially interfering effects on surrounding equipment such as communications receivers etc. Standards exist which stipulate the maximum EMI radiation which is permitted. These are referred to as EMC (electromagnetic compatibility) standards. Historically, the focus on reducing EMI radiation has been on enclosures or boxes which surround the electronic equipment mounted within the box. However, with new ICs (integrated circuits) and ASICs (application specific integrated circuits) being designed to operate at faster and faster speeds, individual chips are becoming significant contributors to the EMI problem and it has become important to design IC packages which are effective in reducing EMI, thereby reducing the burden of EMI reduction placed on the enclosures in which the IC packages are to be installed.
Existing methods for the EMC characterization of silicon devices were developed to measure radiation from printed circuit boards in operation inside electronic devices. These methods are not appropriate or capable of characterizing ASIC packages on their own without electronics. From a mechanical package point of view, various methods exist for measuring shielding effectiveness of metal enclosures for electronic equipment. However, these methods are not appropriate for small devices such as an ASIC package.